Extracorporeal Life Support: Physiological Concepts and Clinical Outcomes

The association of off-hour vs. on-hour intensive care unit admission time with mortality in patients with cardiogenic shock: a retrospective multi-centre analysis

AIMS

Studies have shown a so-called off-hour effect for many different diseases, but data are scarce concerning cardiogenic shock. We therefore assessed the association of off-hour vs. on-hour intensive care unit admission with 30-day mortality in patients with cardiogenic shock.

METHODS AND RESULTS

In total, 1720 cardiogenic shock patients (666 admitted during off-hours) from two large university hospitals in Germany were included in retrospect. An admission during off-hours was associated with increased 30-day mortality compared to an admission during on-hours [crude mortality 48% vs. 41%, HR 1.17 (1.03-1.33), P = 0.017]. This effect remained significant after propensity score matching (P = 0.023). Neither patients with a combined SCAI stage D and E (P = 0.088) or C (P = 0.548) nor those requiring cardiopulmonary resuscitation (P = 0.114) had a higher mortality at off-hour admission. In contrast, those without veno-arterial extracorporeal membrane oxygenation [HR 1.17 (1.00-1.36), P = 0.049], without acute myocardial infarction [HR 1.27 (1.02-1.56), P = 0.029] or a with combined SCAI stage A and B [HR 2.23 (1.08-4.57), P = 0.025] had an increased mortality at off-hour admission.

CONCLUSION

Our study showed an increased mortality in patients with cardiogenic shock admitted during off-hours, especially in those with a milder onset of disease. This stresses the importance of a thorough workup of each patient, especially at times of limited resources, the menace of underestimating the severity of cardiogenic shock, and the need for an improved 24×7 available risk stratification.

Novel Left Ventricular Unloading Strategies in Patients on Peripheral Venoarterial Extracorporeal Membrane Oxygenation Support

The purpose of this study was to evaluate left ventricular (LV) unloading strategies in patients supported with peripheral venoarterial extracorporeal membrane oxygenation (VA-ECMO). A retrospective review was conducted of all consecutive patients requiring VA-ECMO support for any indication, who underwent novel LV unloading strategies with either direct left atrial venoarterial (LAVA) cannulation or pulmonary artery venoarterial (PAVA) venting, in comparison to Impella and intra-aortic balloon pump (IABP). The primary outcome was successful bridge to transplant, LV assist device, or myocardial recovery. Forty-six patients (63% male, mean age 52.8 ± 17.6 years) were included. Fourteen patients (30%) underwent novel unloading with either LAVA or PAVA, 11 patients (24%) underwent IABP placement, and 21 patients (46%) underwent Impella insertion. In the novel LV unloading cohort, 10 patients (71%) survived to hospital discharge. Four patients (29%) were weaned from ECMO and eight patients (57%) underwent cardiac transplantation. Although a trend favoring cannula-based unloading for the primary outcome was noted, the cohort was too small for statistical significance (79% LAVA/PAVA, 57% Impella, 45% IABP; p = 0.21). However, probability of survival was greater in the LAVA/PAVA cohort compared to Impella and IABP ( p < 0.05). Thus, we demonstrate the efficacy of LA and PA cannulation as an alternative LV unloading strategy for patients supported with peripheral VA-ECMO.

Prognostic impact of lung computed tomography density in cardiogenic shock patients with veno-arterial extracorporeal membrane oxygenation

BACKGROUND

Pulmonary complications often occur in patients receiving veno-arterial extracorporeal membrane oxygenation (VA ECMO). However, the prognostic impact of lung damage has not been fully elucidated.

METHODS

This single-center retrospective observational study targeted patients with cardiogenic shock who received VA ECMO between 2012 and 2021. This study included 65 patients who underwent chest computed tomography (CT) on VA ECMO, followed by escalation to central mechanical circulatory support (MCS) with left ventricular venting. The average density of lung CT images was measured using region-of-interest methods, and the primary endpoint was 180-day all-cause death after escalation to the central MCS.

RESULTS

Twenty-two patients (34%) developed 180-day all-cause death. According to the Cox regression analysis, age (hazard ratio [HR], 1.08; 95% confidence interval [CI], 1.03-1.14; p = 0.001), ischemic etiology (HR, 5.53; 95% CI, 2.09-14.62; p < 0.001), duration of VA ECMO support (HR, 1.19; 95% CI, 1.00-1.40; p = 0.045), and lung CT density (≥ -481 Hounsfield unit [HU]) (HR, 6.33; 95% CI, 2.26-17.72; p < 0.001) were independently associated with all-cause death. Receiver operating characteristic curve analysis determined that lung CT density ≥ -481 HU is an optimal cutoff value for predicting all-cause death (area under the curve [AUC], 0.72). The 180-day overall survival rate for patients with high lung CT density (≥ -481 HU) was significantly lower than that for those with low lung CT density (< -481 HU) (44.4% vs. 81.6%, respectively, p = 0.002).

CONCLUSIONS

Higher lung CT density could be a useful predictor of death in patients with VA ECMO requiring central MCS escalation.

[Extracorporeal Life Support in Critical Care Medicine]

Veno-arterial extracorporeal life support (ECLS) may be indicated in patients with refractory heart failure. The list of conditions in which ECLS is successfully used is growing and includes cardiogenic shock following myocardial infarction, refractory cardiac arrest, septic shock with low cardiac output and severe intoxication. Femoral ECLS is the most common and often preferred ECLS-configuration in the emergency setting. Although femoral access is usually quick and easy to establish, it is also associated with specific adverse haemodynamic effects due to the direction of blood flow and access-site complications are inherent. Femoral ECLS provides adequate oxygen delivery and compensates for impaired cardiac output. However, retrograde blood flow into the aorta increases left ventricular afterload and may worsen left ventricular stroke work. Therefore, femoral ECLS is not equivalent to left ventricular unloading. Daily haemodynamic assessments are crucial and should include echocardiography and laboratory tests determining tissue oxygenation. Common complications include the harlequin-phenomenon, lower limb ischaemia or cerebral events and cannula site or intracranial bleeding. Despite a high incidence of complications and high mortality, ECLS is associated with survival benefits and better neurological outcomes in selected patient groups.

Radiographic assessment of lung edema (RALE) score is associated with clinical outcomes in patients with refractory cardiogenic shock and refractory cardiac arrest after percutaneous implantation of extracorporeal life support

VA-ECMO is a promising therapeutic option in refractory cardiogenic shock (RCS) and refractory cardiac arrest (RCA). However, increase in left ventricular afterload enhances further reduction of LV contractility and pulmonary edema. The aim of this study was to evaluate pulmonary edema based on the RALE score and the prognostic value of the score on ECLS weaning and mortality. In this retrospective study, data from 40 patients (16 RCAs and 24 RCSs) were analyzed. Demographic, clinical data and the RALE score for evaluating pulmonary edema were assessed. Descriptive statistics, intraclass correlation, and receiver operating characteristic (ROC) curves were computed. Weaning from ECLS was successful in 30 (75%) patients, 16 patients (40%) were discharged alive. Overall, the survivors were younger, presenting with a higher left ventricular ejection fraction (30 ± 2% vs.23 ± 9%;p < 0.01) and a lower initial serum lactate concentration 7.7 ± 4.5 mmol/l vs. 11.5 ± 4.9 mmol/l; p = 0.017). Survivors had lower RALE scores than non-survivors (16.3 ± 9.4 vs. 26.4 ± 10.4; p = 0.0034). The interobserver variability of the RALE score was good (0.832). The AUC predicting mortality and weaning from ECLS presented comparable results to the established parameters (SAVE, serum lactate). Implementation of the RALE score could support prediction of outcome parameters during VA-ECMO therapy.

Case Report: Left Ventricular Unloading Using a Mechanical CPR Device in a Prolonged Accidental Hypothermic Cardiac Arrest Treated by VA-ECMO - a Novel Approach

We recently treated a 36-year-old previously healthy male with a prolonged hypothermic (lowest temperature 22.3°C) cardiac arrest after an alcohol intoxication with a return of spontaneous circulation after 230min of mechanical cardiopulmonary resuscitation and rewarming by veno-arterial ECMO with femoral cannulation and retrograde perfusion of the aortic arch. Despite functional veno-arterial ECMO, we continued mechanical cardiopulmonary resuscitation (Auto Pulse™ device, ZOLL Medical Corporation, Chelmsford, USA) until return of spontaneous circulation to prevent left ventricular distention from persistent ventricular fibrillation. The case was further complicated by extensive trauma caused by mechanical cardiopulmonary resuscitation (multiple rib fractures, significant hemothorax, and a liver laceration requiring massive transfusion), lung failure necessitating a secondary switch to veno-venous ECMO, and acute kidney injury with the need for renal replacement therapy. Shortly after return of spontaneous circulation, the patient was already following commands and could be discharged 3 weeks later without neurologic, cardiac, or renal sequelae and being entirely well. Prolonged accidental hypothermic cardiac arrest might present with excellent outcomes when supported with veno-arterial ECMO. Until return of spontaneous circulation, one might consider continuing with mechanical cardiopulmonary resuscitation in addition to ECMO to allow some left ventricular unloading. However, the clinician should keep in mind that prolonged mechanical cardiopulmonary resuscitation may cause severe injuries.

Time-Resolved Echo-Particle Image/Tracking Velocimetry Measurement of Interactions Between Native Cardiac Output and Veno-Arterial ECMO Flows

Determination of optimal hemodynamic and pressure-volume loading conditions for patients undergoing veno-arterial extracorporeal membrane oxygenation (VA-ECMO) would benefit from understanding the impact of ECMO flow rates (QE) on the native cardiac output in the admixing zone, i.e., aortic root. This study characterizes the flow in the aortic root of a pig with severe myocardial ischemia using contrast-enhanced ultrasound particle image/tracking velocimetry (echo-PIV/PTV). New methods for data preprocessing are introduced, including autocontouring to remove surrounding tissues, followed by blind deconvolution to identify the centers of elongated bubble traces in images with low signal to noise ratio. Calibrations based on synthetic images show that this procedure increases the number of detected bubbles and reduces the error in their locations by 50%. Then, an optimized echo-PIV/PTV procedure, which integrates image enhancement with velocity measurements, is used for characterizing the time-resolved two-dimensional (2D) velocity distributions. Phase-averaged and instantaneous flow fields show that the ECMO flow rate influences the velocity and acceleration of the cardiac output during systole, and secondary flows during diastole. When QE is 3.0 L/min or higher, the cardiac ejection velocity, phase interval with open aortic valve, velocity-time integral (VTI), and mean arterial pressure (MAP) increase with decreasing QE, all indicating sufficient support. For lower QE, the MAP and VTI decrease as QE is reduced, and the deceleration during transition to diastole becomes milder. Hence, for this specific case, the optimal ECMO flow rate is 3.0 L/min.

Heart failure: role and point of view of cardiac intensivist

Heart failure is an acute or chronic syndrome where the heart is unable to provide adequate amount of oxygen to body tissues. The treatment of heart failure aims to give an immediate answer in terms of regression of volume overload and restoration of hemodynamic stability and then to ensure management of clinical exacerbation, reduction in hospital stay, and increasing of survival. The pharmacological treatment of heart failure includes drugs with different strength of evidence. When the patient is no more responsive to medical therapy a non-pharmacological approach may be required. The first step is cardiac resynchronization therapy and implantable cardiac defibrillator. Then hospitalization and inotropic support may be needed. When cardiac disease reaches the end stage, the severe decrease in multi organ perfusion requires a quick therapeutic response. This is a time dependent scenario, when mechanical circulatory support (MCS) plays a crucial role. MCS may be used as temporary hemodynamic support on situations where myocardial recovery is likely, such as after revascularization and in cases of fulminant acute myocarditis. Conversion to ventricular assist devices or transplantation should be considered if longer duration of MCS is required. Advances in the treatment of cardiogenic shock patients in terms of pharmacological therapies, short term and long term MCS could provide opportunities to improve survival, but they also increase the complexity of clinical care. For this reason a multidisciplinary shock team approach is paramount for early symptom detection, to guide initial haemodynamic therapy and for the right choice of MCS device at the right time.

The Physiologic Basis and Clinical Outcomes of Combined Impella and Veno-Arterial Extracorporeal Membrane Oxygenation Support in Cardiogenic Shock

Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) provides effective hemodynamic support in cardiogenic shock, but in some cases may be complicated by left ventricular (LV) distension and pulmonary edema. The Impella, a catheter-mounted microaxial pump has been used to unload the LV. Recent studies have compared the clinical outcomes of VA-ECMO to the combination of Impella and VA-ECMO. The purpose of this review is threefold: firstly, to discuss the physiological effects of Impella support in addition to VA-ECMO, secondly to review published studies on the outcome of this combined support, and thirdly to provide a practical overview of the approach to combining Impella and VA-ECMO.

Dual RVAD-ECMO Circuits to Treat Cardiogenic Shock and Hypoxemia Due to Necrotizing Lung Infection: A Case Report

Utilization of venoarterial extracorporeal membrane oxygenation (VA-ECMO) is expanding, but dual VA-ECMO circuits to treat cardiogenic shock with refractory hypoxemia is unreported. We describe the case of combined cardiogenic and distributive shock due to necrotizing pulmonary blastomycosis. After initial central VA-ECMO cannulation, acute respiratory distress syndrome (ARDS) with increasing shunt resulted in significant central hypoxemia due to progressive ventilation-perfusion mismatch. An additional circuit provided complete oxygenation of the high circulating volume. After 4 months on support, he underwent successful heart-lung-kidney transplantation. Dual ECMO circuits are technically feasible and may be advantageous in specific circumstances of high pulmonary shunting resulting in excessive hypoxemia unbalanced with appropriate oxygen delivery.

Predicting Survival After VA-ECMO for Refractory Cardiogenic Shock: Validating the SAVE Score

Background

Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) is used increasingly to support patients who are in cardiogenic shock. Due to the risk of complications, prediction models may aid in identifying patients who would benefit most from VA-ECMO. One such model is the Survival After Veno-Arterial Extracorporeal Membrane Oxygenation (SAVE) score. Therefore, we wanted to validate the utility of the SAVE score in a contemporary cohort of adult patients.

Methods

Retrospective data were extracted from electronic health records of 120 patients with cardiogenic shock supported with VA-ECMO between 2011 and 2018. The SAVE score was calculated for each patient to predict survival to hospital discharge. We assessed the SAVE score calibration by comparing predicted vs observed survival at discharge. We assessed discrimination with the area under the receiver operating curve using logistic regression.

Results

A total of 45% of patients survived to hospital discharge. Survivors had a significantly higher mean SAVE score (–9.3 ± 4.1 in survivors vs –13.1 ± 4.4, respectively; P = 0.001). SAVE score discrimination was adequate (c = 0.77; 95% confidence interval 0.69-0.86; P < 0.001). SAVE score calibration was limited, as observed survival rates for risk classes II-V were higher in our cohort (II: 67% vs 58%; III: 78% vs 42%; IV: 61% vs 30%; and V: 29% vs 18%).

Conclusions

The SAVE score underestimates survival in a contemporary North American cohort of adult patients with cardiogenic shock. Its inaccurate performance could lead to denying ECMO support to patients deemed to be too high risk. Further studies are needed to validate additional predictive models for patients requiring VA-ECMO.

Pulmonary complications associated with veno-arterial extra-corporeal membrane oxygenation: a comprehensive review

Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) is a life-saving technology that provides transient respiratory and circulatory support for patients with profound cardiogenic shock or refractory cardiac arrest. Among its potential complications, VA-ECMO may adversely affect lung function through various pathophysiological mechanisms. The interaction of blood components with the biomaterials of the extracorporeal membrane elicits a systemic inflammatory response which may increase pulmonary vascular permeability and promote the sequestration of polymorphonuclear neutrophils within the lung parenchyma. Also, VA-ECMO increases the afterload of the left ventricle (LV) through reverse flow within the thoracic aorta, resulting in increased LV filling pressure and pulmonary congestion. Furthermore, VA-ECMO may result in long-standing pulmonary hypoxia, due to partial shunting of the pulmonary circulation and to reduced pulsatile blood flow within the bronchial circulation. Ultimately, these different abnormalities may result in a state of persisting lung inflammation and fibrotic changes with concomitant functional impairment, which may compromise weaning from VA-ECMO and could possibly result in long-term lung dysfunction. This review presents the mechanisms of lung damage and dysfunction under VA-ECMO and discusses potential strategies to prevent and treat such alterations.

Imaging of Cardiac Support Devices

Patients hospitalized in the intensive care unit (ICU) often have multiple support lines and devices that need routine imaging evaluation by radiologists. In patients with cardiogenic shock or depressed cardiac function, mechanical circulation support devices are used in combination with medical therapies to improve patient outcomes and sometimes can stabilize patients for surgical intervention. This article discusses some of the more commonly encountered mechanical circulation devices seen in ICU patients, including intra-aortic balloon pumps, Impella devices, extracorporeal membrane oxygenation cannulas, and ventricular assist devices. Normal appearance and commonly encountered device-related complications that can be diagnosed on imaging are reviewed.

Medical Optimization and Liberation of Adult Patients From VA-ECMO

Venoarterial extracorporeal membrane oxygenation (VA-ECMO) can be an efficacious cardiopulmonary support for adults as rescue from refractory cardiogenic shock. It is best employed as a bridging strategy to recovery or alternative support rather than sustained, long-term mechanical circulatory support. The purpose of this paper is to discuss strategies to optimize patient management on VA-ECMO and approaches to promote successful separation from support. Rapid medical optimization will assist in reducing the time on VA-ECMO, thereby improving the likelihood of patient salvage. Suitably trained physicians and personnel, guided by structured protocols, can promote excellence in team care and provision of consistent management. Focusing on anticoagulation, careful neurologic monitoring, prevention of leg ischemia, awareness of differential hypoxemia, optimizing mechanical ventilation, identifying and timely intervention for left-ventricular distension (LVD), along with a strategic weaning algorithm, can prevent significant morbidity and mortality. LVD physiology, diagnosis, and risk factors are reviewed. Indications for LV decompression, along with medical and mechanical management options, are elucidated.

Cardiogenic Shock Due to End-Stage Heart Failure and Acute Myocardial Infarction: Characteristics and Outcome of Temporary Mechanical Circulatory Support

BACKGROUND

Mechanical circulatory support (MCS) is increasingly used in cardiogenic shock, but outcomes may differ between patients with acute myocardial infarction (AMI) or end-stage heart failure (ESHF). This study aimed to describe the characteristics of patients with cardiogenic shock due to AMI and ESHF.

METHODS

Single-center study of consecutive patients with cardiogenic shock due to AMI (n = 26) and ESHF (n = 42) who underwent MCS (extracorporeal life support, Impella or temporary ventricular assist devices). Arterial and venous O2 content and CO2 tension (PCO2), O2-hemoglobin affinity (P50) were measured. Veno-arterial difference in PCO2/arterio-venous difference in O2 content ratio was derived. Acid-base balance was characterized by the Gilfix method. MCS-related complications that required intervention or surgery were collected.

RESULTS

Patients with ESHF had lower ejection fraction, higher right and left-sided filling pressures, pulmonary artery pressure and vascular resistance, lower oxygen delivery (DO2) compared with AMI, which was not fully compensated by the increased hemoglobin P50. As a result, patients with ESHF had higher veno-arterial difference in PCO2 relative to arterio-venous difference in O2 content. Despite greater anerobic metabolism, patients with ESHF had less severe metabolic acidosis and base deficit compared with AMI, predominantly due to differences in strong ions.

CONCLUSION

The cardiogenic shock phenotype in ESHF was distinct from AMI, characterized by higher filling and pulmonary artery pressures, lower DO2, greater anaerobic metabolism but less severe metabolic acidosis.

Complications of veno-arterial extracorporeal membrane oxygenation for refractory cardiogenic shock or cardiac arrest

Background:

The frequency of using veno-arterial extracorporeal membrane oxygenation increased, especially in patients with refractory cardiogenic shock or cardiac arrest. However, data of complications of veno-arterial extracorporeal membrane oxygenation are lacking. This study sought to investigate the incidence of veno-arterial extracorporeal membrane oxygenation complications for acute myocardial infarction patients with refractory cardiogenic shock or cardiac arrest and its relationship with patient survival.

Methods:

This study included 151 consecutive patients who underwent veno-arterial extracorporeal membrane oxygenation between 2006 and 2018 at a single referral center. We divided the patients into those who survived for 30 days after veno-arterial extracorporeal membrane oxygenation ( n = 57, 38%; group 1) and those who died within 30 days after veno-arterial extracorporeal membrane oxygenation support ( n = 94, 62%; group 2). The major adverse clinical events associated with veno-arterial extracorporeal membrane oxygenation were defined as first occurrence of infection, major bleeding, and stroke.

Results:

Adverse clinical events associated with veno-arterial extracorporeal membrane oxygenation occurred in 34 (59.6%) and 56 (59.6%) patients in groups 1 and 2, respectively. Group 2 had more patients who underwent new renal replacement therapy (21.1% vs 37.2%, p = 0.037). After multivariable analysis, cardiac arrest was independently associated with 30-day mortality (odds ratio = 3.6; 95% confidence interval = 1.7–7.63; p = 0.001). After excluding patients who died within 48 h after undergoing veno-arterial extracorporeal membrane oxygenation, new renal replacement therapy (odds ratio = 4.47; 95% confidence interval = 1.58–12.61; p = 0.005) and major adverse clinical events (odds ratio = 2.66; 95% confidence interval = 1.01–7.03; p = 0.049) were independently associated with 30-day mortality.

Conclusion:

Although veno-arterial extracorporeal membrane oxygenation can improve the survival, it is associated with morbidity. Therefore, risk–benefit analysis for veno-arterial extracorporeal membrane oxygenation and prevention of complications are important to improve prognosis.

ECMO support in cardiac intervention of severe pulmonary stenosis: A case report

RATIONALE

Patients of critical pulmonary artery stenosis would face severe hypoxemia, cardiac failure as well as massive hemorrhage during percutaneous balloon dilation and pulmonary arterial stent implantation. Here, we present a case in which the elective use of extracorporeal membrane oxygenation (ECMO) support successfully facilitated safe percutaneous balloon dilation of pulmonary artery and stent implantation on a patient with severe pulmonary artery stenosis caused by aorto-arteritis.

PATIENT CONCERNS

A 47-year-old man was hospitalized due to 10 years of post-exercise exhaustion and shortness of breath. Half a month ago the symptoms deteriorated. He also manifested systemic edema and could only sit upright to breath during night time. Computed tomographic angiography (CTA) indicated severe pulmonary stenosis caused by aorto-arteritis.

DIAGNOSES

Right pulmonary artery stenosis, left pulmonary artery occlusion, severe tricuspid regurgitation, right atrium, and ventricle enlargement, atrial fibrillation with rapid ventricular rates, NYHA class IV, pulmonary infection.

INTERVENTIONS

V-A ECMO support was considered during percutaneous balloon dilation of pulmonary artery and stent implantation.

OUTCOMES

The patient remained hemodynamically stable throughout the procedure with no inotropic support. ECMO was successfully weaned off after the intervention, with no procedural complications. Postoperative echocardiography indicated much better heart function, and he was discharged uneventfully 5 days later.

CONCLUSION

V-A ECMO is capable of preventing hypoxemia and providing effective circulation support during cardiac intervention in patients of severe pulmonary stenosis.

A life support-based comprehensive treatment regimen dramatically lowers the in-hospital mortality of patients with fulminant myocarditis: a multiple center study

Fulminant myocarditis (FM) has unacceptable high mortality. This study aimed to evaluate the therapeutic efficacy of a life support-based comprehensive treatment regimen (LSBCTR), a completely novel treatment regimen, for FM. A total of 169 FM patients recruited from January 2008 to December 2018 were divided into two groups: patients receiving LSBCTR (81 cases), which includes (i) mechanical life support (positive pressure respiration, intra-aortic balloon pump with or without extracorporeal membrane oxygenation), (ii) immunomodulation therapy using sufficient doses of glucocorticoids and immunoglobulins, and (iii) application of neuraminidase inhibitors, and those receiving conventional treatment (88 cases). The endpoints were in-hospital death and heart-transplantation. Of all the population, 44 patients (26.0%) died in hospitals. In-hospital mortality was 3.7% (3/81) for LSBCTR group and 46.6% (41/88) for traditional treatment (P<0.001). Early application of LSBCTR, mechanical life support, neuraminidase inhibitors, and immunomodulation therapy significantly contributed to reduction in in-hospital mortality. This study describes a novel treatment regimen for FM patients that dramatically reduces in-hospital mortality. Its generalization and clinical application will efficiently save lives although further optimization is needed. This study offers an insight that virus infection induced inflammatory waterfall results in cardiac injury and cardiogenic shock and is the therapeutic target.

Left ventricular decompression in veno-arterial extracorporeal membrane oxygenation

Background

Despite the survival benefit of veno-arterial extracorporeal membrane oxygenation (VA-ECMO) for treatment of refractory cardiogenic shock, it can also have potentially deleterious effects of left ventricular overload and pulmonary edema. The objective of this review was to investigate the current evidence on the incidence, diagnosis, risk factors, prevention, and interventions for left ventricular overload in adult and pediatric VA-ECMO patients.

Methods

Five electronic databases, including MEDLINE, EMBASE, PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), and Cochrane Database of Systematic Reviews, were searched for original published studies from their dates of inception to January 2018. All types of adult and pediatric studies that investigated LV overload in VA-ECMO and were published in the English language were reviewed. Exclusion criteria included abstracts and conference presentations.

Results

The reported incidence and sequelae of LV overload in VA-ECMO are highly variable, with presentations ranging from pulmonary arterial diastolic pressures of greater than 25 mmHg and LV distention on echocardiography, to severe pulmonary edema, LV thrombosis, and refractory ventricular arrhythmias. Currently, there are no standardized diagnostic criteria or guidelines for the type and timing of intervention for LV overload. Techniques for LV decompression have included direct surgical LV venting with catheter insertion via sternotomy or a minimally invasive incision; percutaneous catheterization via a transaortic, transseptal, or transpulmonary approach; ventricular assist devices; and intra-aortic balloon pumps.

Conclusions

Left ventricular volume distention is a significant problem in VA-ECMO patients, with sequelae including myocardial ischemia, severe pulmonary edema, and intracardiac thrombosis. Further research is required on its incidence, diagnostic criteria, and risk factors, as well as the optimal timing and method for LV decompression, given the diversity of surgical and percutaneous techniques that are available.

Mechanical circulatory support as bridge therapy for heart transplant: case series report

BACKGROUND

Mechanical circulatory support (MCS) represents an effective urgent therapy for patients with cardiac arrest or end-stage cardiac failure. However, its use in developing countries as a bridge therapy remains controversial due to costs and limited duration. This study presents five patients who underwent MSC as bridge therapy for heart transplantation in a developing country.

CASE PRESENTATION

We present five patients who underwent MCS as bridge therapy for heart transplant between 2010 and 2015 at Fundación Cardioinfantil-Instituto de Cardiología. Four were male, median age was 36 (23-50) years. One patient had an ischemic cardiomyopathy, one a lymphocytic myocarditis, two had electrical storms (recurrent ventricular tachycardia) and one an ischemic cardiomyopathy with an electrical storm. Extracorporeal life support (ECLS) was used in three patients, left ventricular assistance in one, and double ventricular assistance in one (Levitronix^® Centrimag^®). Median assistance time was 8 (2.5-13) days. Due to the inability of cardiopulmonary bypass weaning, two patients required ECLS after transplant. One patient died in the intensive care unit due to type I graft rejection. Endpoints assessed were 30-day mortality, duration of bridge therapy and complications related to MCS. Patients that died on ECLS, or were successfully weaned off ECLS were not included in this study.

CONCLUSIONS

MCS is often the only option of support for critically ill patients waiting for a heart transplant and could be considered as a short-term bridge therapy.

'Combat' Approach to Cardiogenic Shock

The incidence of cardiogenic shock is rising, patient complexity is increasing and patient survival has plateaued. Mirroring organisational innovations of elite military units, our multidisciplinary medical specialists at the INOVA Heart and Vascular Institute aim to combine the adaptability, agility and cohesion of small teams across our large healthcare system. We advocate for widespread adoption of our 'combat' methodology focused on: increased disease awareness, early multidisciplinary shock team activation, group decision-making, rapid initiation of mechanical circulatory support (as appropriate), haemodynamic-guided management, strict protocol adherence, complete data capture and regular after action reviews, with a goal of ending preventable death from cardiogenic shock.

Differential responses to larger volume intra-aortic balloon counterpulsation: Hemodynamic and clinical outcomes

Objectives

Examine hemodynamic and clinical correlates of use of an intra‐aortic balloon pump catheter in a single center.

Background

The intra‐aortic balloon pump catheter (IABC) has been used for 50 years but the clinical benefit is still debated. We reviewed 76 patients with right heart catheter measurements prior to IABC to assess response and outcomes.

Methods

All patients who received IABC with a 50cc balloon for at least 1 hour were included in this retrospective chart review study. Demographics, comorbidities, lab values, and hemodynamic parameters were recorded at baseline and 15 h postinsertion.

Results

Seventy‐six patients had paired measurements of cardiac output. 60 patients had a higher cardiac output with IABC treatment (responder group) and 16 did not (nonresponders). In the 60 patients in the responder group, cardiac output and index significantly increased from baseline 3.6 ± 1.3 L/min to 5.2 ± 1.8 L/min, and 1.8 ± 0.5 L/min/m² to 2.6 ± 0.8 L/min/m² respectively following IABC placement (P < 0.0001 for both comparisons). Various hemodynamic variables were examined and the best predictor of response to IABC was a cardiac power index of 0.3 or less. Regardless of response, in hospital survival was similar between groups.

Conclusions

The majority of patients improve their cardiac output with IABC but survival was unchanged. Further work into the pathophysiology of cardiogenic shock is needed.

Cardiac Support: Emphasis on Venoarterial ECMO

Major advances have been made in mechanical circulatory support in recent years. Venoarterial (VA) extracorporeal membrane oxygenation (ECMO) provides both pulmonary and circulatory support for critically ill patients with hemodynamic compromise, serving as a bridge to recovery or definitive therapy in the form of transplant or a durable ventricular assist device. In the past, VA ECMO support was used in cases of cardiogenic shock or failure to wean from cardiopulmonary bypass; however, the technology is now being applied to an ever-expanding list of conditions, including massive pulmonary embolism, cardiac arrest, drug overdose, and hypothermia.

Extracorporeal Membrane Oxygenation (ECMO) and the Critical Cardiac Patient

PURPOSE OF REVIEW

This review is to summarize the basics of veno-arterial (VA) extracorporeal membrane oxygenation (ECMO) as it is utilized for critically ill cardiac patients.

RECENT FINDINGS

ECMO may be instituted in a variety of health care settings, from the emergency room to the operating room. The types of patients who may benefit from ECMO are reviewed in detail. The complications of ECMO are reviewed, including access-related issues and hematologic and neurologic problems. The principles of weaning of ECMO are described.

CONCLUSION

Due to its versatility and relatively low cost, VA ECMO use is sharply increasing worldwide. It is important to select patients carefully for this mode of therapy as it can keep patients alive even in states of severe neurologic impairment or multiorgan failure. Short courses of ECMO may allow critically ill patients to be salvaged, but ultimately survival depends on resolution of the underlying problem or ability to transition to another more durable mode of cardiac support.